Polyvalent bacterial lysate (respiratory) (PBL)

Polyvalent bacterial lysates (PBLs) are immunomodulatory preparations composed of inactivated antigens and cell wall fragments from a variety of common respiratory pathogens, such as Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus (Frontiers in Immunology, 2022). These lysates act as pathogen-associated molecular patterns (PAMPs) that are recognized by the innate immune system through pattern recognition receptors like Toll-like receptors (TLRs) (NIH, 2024). Upon oral administration, the antigens are sampled by M cells in the gut-associated lymphoid tissue (GALT), initiating a cascade that activates dendritic cells, T cells, and B cells (ResearchGate, 2025). This process enhances the production of secretory IgA (sIgA) in the respiratory tract, providing a robust mucosal defense against both bacterial and viral infections (NIH, 2026). PBLs are primarily utilized as prophylactic treatments to reduce the frequency and severity of recurrent respiratory tract infections and exacerbations in patients with chronic bronchitis, COPD, or asthma (NIH, 2024). By modulating the Th1/Th2 balance and promoting anti-inflammatory cytokine production, they help maintain respiratory homeostasis and reduce the clinical reliance on antibiotics (Frontiers in Immunology, 2022).

Other names

Bacterial antigens from inactivated respiratory pathogensBacterial lysatePolyvalent mechanical bacterial lysatePMBLPolyvalent chemical bacterial lysatePCBLOM-85Bacterial extractInactivated respiratory bacterial antigens

Stimulation of Toll-like receptors (TLRs), particularly TLR-2 and TLR-4, on dendritic cells and macrophages within the gut-associated lymphoid tissue (GALT) (NIH, 2024). This interaction promotes the maturation of antigen-presenting cells, triggers the release of cytokines such as IL-10 and IFN-gamma, and activates T and B lymphocytes, ultimately leading to increased levels of secretory IgA (sIgA) in the respiratory mucosa to enhance pathogen clearance (ResearchGate, 2025; NIH, 2026).